In a significant victory for Tribal Nations and environmental advocates, the Michigan Supreme Court has overturned a key permit authorizing Enbridge Energy’s proposed Line 5 tunnel beneath the Straits of Mackinac, sending the project back to the Michigan Public Service Commission (MPSC) for a new review.
In its decision, the state’s highest court ruled that the MPSC violated the Michigan Environmental Protection Act (MEPA) and failed to fulfill its obligations under Michigan’s public trust doctrine when it approved Enbridge’s tunnel permit in 2023. The ruling requires the commission to reconsider the application using the legal standards outlined by the court.
The proposed project would relocate a four-mile segment of the Line 5 pipeline into a tunnel beneath the Straits of Mackinac. Enbridge has argued the tunnel would reduce the risk of an oil spill in the Straits, while Tribal Nations and environmental organizations contend the project would prolong the life of an aging pipeline and threaten one of North America’s most ecologically significant freshwater systems.
